Controller



1952 w. s. HOLZBOCK 3,064,682

CONTROLLER Filed June 6, 1960 INV EN TOR.

WERNER G. HOLZBOCK 3,064,682 CONTROLLER Werner G. Hoizbocir, Nashua,N.H., assignor to Vickers Incorporated, Troy, Mich, a corporation ofMichigan Filed June 6, 1966. Ser. No. 34,203 9 Claims. (Cl. 137-623)This invention relates to an electro-hydraulic controller, and moreparticularly to a single-stage electro-hydraulic servo'valve adapted forthe proportional control of fluid flow and pressure.

The controller of the invention utilizes in a novel way, the jet pipeprinciple of operation, but differs from the jet pipe controllers of theprior art in many important respects such as, for example, it has nobearings, elimination of sharp internal bends which produce pressurelosses is effected, provision is made to balance flow forces thusallowing virtually frictionless operation, freedom from silting andclogging is made possible, more compactness is achieved, and coupledwith the latter, is reduction in size for comparable operating range.

The main object of this invention is to provide a single stageelectro-hydraulic controller which utilizes the jet pipe principle ofoperation in a novel and improved way.

A more specific object of this invention is to provide anelectro-hydraulic controller of more compactness and of reduced size.

Another specific object of this invention is to provide anelectro-hydraulic controller wherein flow forces are balanced to allowvirtually frictionless operation.

Still another object is to provide an electro-hydraulic controllerwherein sharp internal bends are avoided thus reducing pressure losses.

Another object of the invention is to provide an electrohydrauliccontroller wherein bearings are eliminated.

These and further objects and features of the invention will become moreapparent from the following description and accompanying drawingwherein:

FIG. 1 is a vertical section view of an electro-hydraulic controllerembodying the principles of the invention;

FIG. 2 is a section view generally as seen along line 2 2 in FIG. 1; and

FIG. 3 is a view generally as seen from line 33 in EEG. 1.

Referring now to the drawing, the numeral 6 identifies a controllerembodying the principles of the invention, which includes a main block,or housing 8 to which is aflixed an assemblage including a magnet coverplate 10, and a magnet housing 12. The main block 8, which issubstantially cubic in form, has a circular recess 14 pro- I vided on aside surface, while on the opposite surface is provided a circularrecess 16. A bore, or passageway 18 is centrally arranged in the mainblock 8 and extends between the circular recesses 14 and 16. An opening20, of successively reduced diameters, extends upwardly from the bottomof the housing 8 and intersects the passageway 1'8. A second opening 22,of successively reduced diameter, extends downwardly from the topsurface of the housing 8 and intersects the passageway 18. It will beseen that the axis of the openings 29 and 22 coincide. The opening 22 isthreaded to receive a pipe fitting whereby the controller may beconnected via a pipe or tubing (not shown) to a source of high pressurehydraulic fluid. A third opening 24, formed on the rear surface of thehousing 8, extends inwardly and is connected by a passageway 26 to theopening 18, as best seen in FIG. 2. The opening 24 is threaded toreceive a pipe connection for conduction of hydraulic fluid via a pipeor tubing (not shown), back to a reservoir, from whence it is pumpedunder pressure to the controller, in the well known manner.

Slidably positioned within the passageway '18 is a jet rates atent @135iee assess? Patented Nov. 20, 1952 spool, or piston 28 which has aconically shaped hole, or passageway 36* formed in its mid-region. Theupper, or larger end of the hole 3% is arranged adjacent the lowermostend of the opening 22, while the lower end, or smallest diameter end ofthe hole 34 opens into the opening 20.

Secured within the opening 20 by means of a pair of straps 32, is a jetstream receptor means in the form of a distributor block 34, which has afrusto-conical projection 36 formed on its upper surface. A pair ofpassageways 33, 46 are formed in the projection 36, the upper extremityof which provide ports 42, 44 respectively, located on the upper surfaceof the projection 36, While the lower end of said passageways lead toopenings 46, 43 respectively, extending upwardly within the distributorblock 34. The openings 46, 48 are threaded to receive pipe connectionsfor conduction of hydraulic pressure fluid through a pipe, or tubing(not shown) leading to an actuating mechanism to be driven by thecontroller 6. It will be seen in FIG. 3, that the ports 42, 44 are on aline coincident with the longitudinal axis of the jet piston 28;accordingly, horizontal movement of the jet piston 28 will directhydraulic pressure fluid from the lower end of the conical passageway36, to one or the other of the ports. In such manner, the recoveredhydraulic pressure within openings 46 and 48, which may be between 80 to95 percent of supply pressure, will depend upon the position of the jetpiston 23 relative to the ports 42 and 44 respectively. It is to benoted that the large diameter of the flow passages practicallyeliminates all possibilities from silting and clogging.

The straps 32, which are secured to the lower surface of the main block8 by fastening means such as screws 5%, are each provided with anadjusting screw 52 adapted to abut the lower surface of the distributorblock 34 and maintain the latter in fixed position within the opening29. in such manner, the ports 42, 44 may be adjusted relative to theopening of the passageway 30 formed in the jet piston 28. Gasket means54 may be interposed between the distributor block 34 and the portion ofthe housing within the opening 2% against which the distributor blockseats, said gasket 54 serving dual purposes, namely, to seal the volumeabout the projection 36, and to act as a shim means for regulating thedistance between the top surface of the projection 36 and the opening ofthe conical passageway 3t). It will be seen that hydraulic pressurefluid impinging upon the upper surface of the conical projection 36,which does not enter either of the passageways 38, 46, wili flow fromthe enclosed volume surrounding the projection 36 via passageway 26 intothe opening 24 and back to the hydraulic pump reservoir.

Means to provide hydraulic balance to the jet piston 28 are provided inthe controller of the invention. Such balancing means includes apassageway 56 which leads from the opening 22 into a horizontallyarranged passageway 58 formed in the housing 8. Extending inwardly fromthe passageway 5'8 are a pair of passageways 61) which intersect a pairof vertically arranged passageways 62, the upper end of each openinginto the passageway 18. The jet piston 28 is formed with a pair ofcircular recesses 64 arranged on the lower peripheral surface and in theregion of the opening of passageways 62. It will be seen that thepressure of the inlet hydraulic fluid in opening 22 will be exerted uponthe underside of the jet piston 23 by virtue of the passagewayarrangement 56, 5'8, 66, and 62. In such manner, the downward thrust ofthe hydraulic fluid flowing out of the opening 22 and into the conicalpassageway 30, as well as the weight of the piston 28, and attachedelements, will be counterbalanced by the pressure of fluid actingupwardly within the circular recesses 64 of the jet piston 28.

Aflixed within the circular recess 16, is a stop plate 66 epeaeszdetermined distance to regulate the left end travel of the jet piston28. A bolt, or stud means 89 is axially secured to the other end of the.jet piston 23, which stud is arranged for support of a voice coilassemblage 82. A bolt, or screw 84 is arranged to extend through (withsuflicient clearance) the voice coil assemblage 82, and to be screwedinto the bottom surface of the circular recess 14; by adjusting theposition of the head of the screw 84 relative to the, voice coilassemblage 82, the rightward maximum travel of the voice coil assemblagemay be controlled.

The. voice coil assemblage includes windings 86 arranged for aXialmovement within a circular gap 83 provided between. a magnet centerpiece i l} and the magnet cover plate 16. The magnet center piece 9% isafiixed to a permanent magnet 92 which is secured within the magnethousing 12. It will be seen that with the above described arrangement, amagnetic circuit is provided which passes from the magnet 92, throughthe magnet center piece 99, across the circular gap 83, through themagnet cover plate 10, and through the magnet housing l2 back to themagnet 92. In such manner, a constant flux field is provided in thecircular gap 88.

The voice coil has two windings; a signal winding and a bias winding.Input signals from 30 milliwatts to 5 watts can be accommodated. Thesignal winding is for positioning the piston 28 in accordance with anelectrical input signal. The bias winding is used to obtain a centerposition of the piston for any desired base valve of the control signalthat is applied to the signal winding. The bias signal remains constant,while the control signal may vary above or below a given base value,thus positioning the piston 28 against the forceof the tension spring72. The spring rate determines the amount which the piston moves for agiven increment of control signal; it thus dotermines the range. Theposition of the piston will be proportional to the input signal. Thebias winding is connected to a constant DC. voltage source. The currentflow through the winding is adjustable by potentiometer, or similarmethod which makes fast zeroing of the device possible. Instead ofapplying a constant current to the bias winding, a feedback signal fromthe final control element (not shown) may be used.

Another type of constant force bias, which may be practical in certaininstallations, would involve the use of'a liquid column of predeterminedlevel or head, the pressure of which would be applied to one end of thepiston 28.

It is customary to have a spring determine both bias and range in manyelectro-hydraulic controllers. The bias is then obtained by thenecessary precompression or preextension of the spring. This limits suchdevices to comparatively large ranges, i.e., large signals for a givenmotion of the piston. The reason for such limitation is that forpractical considerations, comparatively large spring rates must be used,otherwise the spring will be too long if it is to provide the requiredpretension or precompression. The arrangement in the controller of theinvention, provides a constantnot a springsignal force, hence, permitsoperation with very small ranges.

A coverplate 94 is aflixed to the housing 8 to enclose the circularrecess 16. Passageway means 95 are arranged to co nect the region ateach end of the jet piston 2 8,with the opening 24; in such manner, theliquid which leakspast the ends of the jet piston 28 is channeled intothe return flow liquid circuit; As an alternative, the region at eachend of the jet piston may be connected to the d inlet opening 22, ifdesired, by suitable passageway means.

The terminal block 1% is arranged within the recess 93. It is adaptedfor electrical connection with the windings as. The passageway r02connects the recess 93 with a threaded opening 1&4 formed in the housing8, which opening 104 is adapted to receive an electrical connector (notshown) for wires which are brought to the controller for connection tothe terminal block 1%. V

The foregoing description has been given in detail without thought tolimitation since the inventive principles involved are capable ofassuming other forms without departing from the spirit of the inventionor the scope of the following claims.

What is claimed is:

1. An electro-hydraulic controller comprising in combination a housing,a distributor block being formed to provide a jet stream receptor means,said housing being formed with an opening adapted to receive and directa hydraulic jet stream toward the distributor block, a piston meanspositionable in a passageway formed in said housing and in opencommunication with said opening, said piston means being in slidingengagement with the wall of said passageway and movable normal to saidjet stream and having a passageway positionable in the path of said jetstream said passageway tapering toward a minimum diameter in the jetdownstream direction, and electro-magnetic means for moving said pistonmeans.

2. An electro-hydraulic controller comprising in combination a housing,a distributor block being formed to provide a jet stream receptor means,said housing being formed with an opening adapted to receive and directa hydraulic jet stream toward the distributor block, a piston meanspositionable in a passageway formed in said housing and in opencommunication with said opening, said piston means being in slidingengagement with the wall of said passageway and movable normal to saidjet stream and having a passageway positionable in the path of said jetstream, said passageway tapering toward a minimum diameterin the jetdownstream direction, said passageway being adapted to cause deflectionof the flow of said jet stream relative to said distributor block, anelectromagnetic means for moving said piston means in a first direction,and means for moving said piston means in a second direction.

3. An electro-hydraulc controller comprising in combination a housing, adistributor block being formed to provide a jet stream receptor meansand having at least one passageway means one end of which is defined bya port on an upper surface of the distributor block, said housing beingformed with an opening adapted to receive and direct a jet stream towardthe distributor block, a piston means positionable in a passagewayformed in said housing and in open communication with said opening, saidpiston means being in sliding engagement with the wall of saidpassageway and movable normal to said jet stream andhaving a passagewaypositionable in the path of said jet stream, which passageway is taperedto a minimum diameter in the jet downstream direction, said passagewaybeing adapted to cause deflection of the flow of said jet stream towardand into said port means, an electromagnetic means for moving saidpiston means, and a spring means afiixed to said piston means.

4. An ele-ctro-hydraulic controller comprising in combination a housing,a distributor block positioned in the housing and being formed toprovide a jet stream receptor and having a pair of passageways one endof each being defined by a port located on an upper surface of thedistributor block, said housing being formed with an opening adapted toreceive and direct a jet stream toward the distributor block, a pistonmeans positionable in a passageway formed in said housing and in opencommunication with said opening, said piston means being in slidingengagement with the wall of said passageway and movable normal to saidjet stream and having a passageway posi-' tionable in the path of saidjet stream, which passageway is tapered to a minimum diameter in the jetdownstream direction, said passageway being adapted to cause deflectionof the flow of said jet stream from one to the other of said ports, anelectro-magnetic means for moving said piston means, and a spring meansarranged to resist movement of said piston means.

5. A11 electro-hydraulic controller comprising in combination a housing,a distributor block positioned in the housing and being formed toprovide a jet stream receptor and having a pair of passageways one endof each being defined by a port located upon an upper surface of thedistributor block the other end of each passageway leading to one of apair of openings formed in the distributor block, said housing beingformed with an opening adapted to receive and direct a jet stream towardsaid distributor block, a passageway formed with its longitudinal axisnormal to the axis of said jet stream opening and having a pistonslidably arranged therein, said piston having a tapered passagewaypositionable in the path of said jet stream for directing the flow ofsaid jet stream to either one or the other of said ports, a passagewaymeans extending between said jet stream opening and said pistoncontaining passageway to direct pressure fluid upon the piston inopposition to the flow of said jet stream, an electromagnetic means formoving said piston, and a spring means arranged to resist movement ofsaid piston.

6. An electro-hydraulic controller according to claim 5 wherein saidelectro-magnetic means includes electric conducting coils movable in amagnetic field.

7. An electro-hydraulic controller according to claim 6 wherein saidmagnetic field is provided by a permanent magnet core.

8. An electro-hydraulic controller according to claim 7 wherein theelectric conducting coils include a bias winding and a signal Winding,said bias winding being arranged for connection to a constant DC.electrical source, while said signal winding is connected to anelectrical input signal source.

9. An electro-hydraulic controller according to claim 5 wherein saiddistributor block is adjustable relative to the tapered passageway ofsaid piston.

Refer nces Cited in the file of this patent UNITED STATES PATENTS 11,320Conard July 18, 1854 1,975,250 Calpha et a1. Oct. 2, 1934 2,672,150Benedict et al Mar. 16, 1954 2,887,623 Bueckcr May 19, 1959 2,932,307Bydale-k Apr. 12, 1960 2,960,995 Hague Nov. 22, 1960 FOREIGN PATENTS475,741 Germany May 1, 1929 511,273 Germany Oct. 28, 1930

